US election 2016: Donald Trump's in trouble

Donald Trump is in trouble. You can't tell from his performances at his campaign rallies. The Republican presumptive presidential nominee remains bullish and combative, but the problems are there.

First he stirred up a controversy with comments about a judge hearing a civil case against him. Even though the judge was born in Indiana, Trump insisted he could not get a fair hearing from the man because he was of Mexican heritage.

The businessman said as he was going to build a wall to keep undocumented immigrants from crossing the Mexican border, the judge, an experienced and respected member of the legal community, would be biased against him.

His remarks, repeated in several media interviews, stirred the Republican establishment. House of Representatives Speaker Paul Ryan, the most senior elected Republican in the country, described the comments as "the textbook definition of a racist comment".

Yet, given that he'd finally endorsed the Republican nominee just a few days before, he insisted he still had his support.

The NRA, who had endorsed Trump at its national convention just two weeks ago, said it was happy to meet. But many supporters were furious the Republican nominee would even consider changes to gun legislation.

Right-wing blogger Erik Erikson wrote: "This is a terrible idea and a flat-out cave by Donald Trump. You cannot deny constitutional rights to American citizens because the government is suspicious of you."

If all that wasn't enough, new opinion polls show that firstly Trump is falling behind Hillary Clinton in the national polls.

And another poll says Trump's standing with the American public has deteriorated significantly. A man who has already borne the burden of being the least popular presidential candidate in modern American political history pushed that barrier a little further. Now 70 percent of the electorate view him negatively, 56 percent feel "strongly unfavourable".

There's a long way to go until the election, but the events of the last two weeks and the new polls tell the same story. Trump's in trouble.